Abstract: At approximately 9:46 a.m. on March 4, 1993, an explosion occurred in the boiler room at American Rubber Products Corporation (ARPC) of Laporte, IN. Thirty employees were in the plant at the time of the explosion. This explosion was caused when a York Shipley gas-fired boiler, serial #7438, exploded without any warning and without any unusual conditions apparent. The blast sent a heavy, 6 foot diameter, boiler end plate through a wall and into the adjacent press department. Escaping scalding water and steam followed the plate into the employees' work area. At the same time, in the opposite direction, the large boiler was propelled through a concrete and brick wall before resting 50 feet outside the building. On the way out, the boiler created a 15 square foot hole in the outside wall. No fire occurred after the incident. Employees #1 through #4 were killed. Employees #5 through #8 were hospitalized and Employees #9 through #14 were treated and released from the nearby hospital emergency room.